Datasheet LTC3853 (Analog Devices) - 4

LTC3853
ELECTRICAL CHARACTERISTICS The
l
denotes the specifications which apply over the full operating junction temperature range, otherwise specifications are at TA = 25°C (Note 3), VIN = 15V, VRUN1,2,3 = 5V, unless otherwise noted. SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
Bottom Gate Off to Top Gate On Delay (Note 6) Top Switch-On Delay Time CLOAD = 3300pF Each Driver 30 ns tON(MIN) Minimum On-Time (Note 7) 90 ns
INTVCC Linear Regulator
VINTVCC Internal VCC Voltage 7V < VIN < 24V 4.8 5 5.2 V INTVCC Load Regulation ICC = 0mA to 50mA 0.5 2 % VEXTVCC EXTVCC Switchover Voltage EXTVCC Ramping Positive l 4.5 4.7 V EXTVCC Voltage Drop ICC = 20mA, VEXTVCC = 5V 30 75 mV EXTVCC Hysteresis 200 mV
Oscillator and Phase-Locked Loop
Nominal Frequency VFREQ = 1.2V 450 500 550 kHz Lowest Frequency VFREQ = 0V 210 250 290 kHz Highest Frequency VFREQ ≥ 2.4V 670 750 830 kHz Channel 2-Channel 1 Phase 120 Deg Channel 3-Channel 2 Phase 120 Deg Channel 1-Channel 3 Phase 120 Deg Channel 2-Channel 1 Phase VFB2 Tied to VIN Through 200kΩ 180 Deg Channel 3-Channel 2 Phase 60 Deg Channel 1-Channel 3 Phase 120 Deg MODE/PLLIN Input Resistance 250 kΩ IFREQ Phase Detector Output Current Sinking Capability fMODE < fOSC –13 µA Sourcing Capability fMODE > fOSC 13 µA
PGOOD Outputs
PGOOD Voltage Low IPGOOD = 2mA 0.1 0.3 V IPGOOD PGOOD Leakage Current VPGOOD = 5V ±2 µA PGOOD Trip Level VFB with Respect to Set Regulated Voltage VFB Ramping Negative –5 –7.5 –10 % VFB Ramping Positive 5 7.5 10 %
Note 1:
Stresses beyond those listed under Absolute Maximum Ratings guaranteed over the –55°C to 150°C operating junction temperature range. may cause permanent damage to the device. Exposure to any Absolute High junction temperatures degrade operating lifetimes; operating lifetime Maximum Rating condition for extended periods may affect device is derated for junction temperatures greater than 125°C. The maximum reliability and lifetime. ambient temperature consistent with these specifications is determined by
Note 2:
The junction temperature, T specific operating conditions in conjunction with board layout, the rated J, is calculated from the ambient temperature T package thermal resistance and other environmental factors. A and power dissipation PD according to the following formulas:
Note 4:
The LTC3853 is tested in a feedback loop that servos VITH1,2,3 to a LTC3853UJ: T specified voltage and measures the resultant V J = TA + (PD • 33°C/W) FB1,2,3.
Note 3:
The LTC3853 is tested under pulsed load conditions such that
Note 5:
Dynamic supply current is higher due to the gate charge being T delivered at the switching frequency. See the Applications Information J ≈ TA. The LTC3853E is guaranteed to meet performance specifications from 0°C to 85°C junction temperature. Specifications over the –40°C section. to 125°C operating junction temperature range are assured by design,
Note 6:
Rise and fall times are measured using 10% and 90% levels. characterization and correlation with statistical process controls. The Delay times are measured using 50% levels. LTC3853I is guaranteed over the –40°C to 125°C operating junction
Note 7:
The minimum on-time condition is specified for an inductor temperature range. The LTC3853H is guaranteed over the –40°C to 150°C peak-to-peak ripple current ≥40% of IMAX (see Minimum On-Time operating junction temperature range and the LTC3853MP is tested and Considerations in the Applications Information section). 3853fc 4 For more information www.linear.com/LTC3853 Document Outline Features Typical Application Description Absolute Maximum Ratings Order Information Pin Configuration Electrical Characteristics Typical Performance Characteristics Pin Functions Functional Diagram Operation Applications Information Typical Applications Package Description Revision History Typical Application Related Parts